/*
 * Copyright (C) 2007 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.testing;

import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import junit.framework.Assert;
import junit.framework.AssertionFailedError;

/**
 * Tests serialization and deserialization of an object, optionally asserting that the resulting
 * object is equal to the original.
 *
 * <p><b>GWT warning:</b> Under GWT, both methods simply returns their input, as proper GWT
 * serialization tests require more setup. This no-op behavior allows test authors to intersperse
 * {@code SerializableTester} calls with other, GWT-compatible tests.
 *
 * @author Mike Bostock
 * @since 10.0
 */
@Beta
@GwtCompatible // but no-op!
public final class SerializableTester
{
    private SerializableTester()
    {
    }

    /**
     * Serializes and deserializes the specified object.
     *
     * <p><b>GWT warning:</b> Under GWT, this method simply returns its input, as proper GWT
     * serialization tests require more setup. This no-op behavior allows test authors to intersperse
     * {@code SerializableTester} calls with other, GWT-compatible tests.
     *
     * <p>Note that the specified object may not be known by the compiler to be a {@link
     * java.io.Serializable} instance, and is thus declared an {@code Object}. For example, it might
     * be declared as a {@code List}.
     *
     * @return the re-serialized object
     * @throws RuntimeException if the specified object was not successfully serialized or
     *                          deserialized
     */
    @SuppressWarnings("unchecked")
    public static <T> T reserialize(T object)
    {
        return Platform.reserialize(object);
    }

    /**
     * Serializes and deserializes the specified object and verifies that the re-serialized object is
     * equal to the provided object, that the hashcodes are identical, and that the class of the
     * re-serialized object is identical to that of the original.
     *
     * <p><b>GWT warning:</b> Under GWT, this method simply returns its input, as proper GWT
     * serialization tests require more setup. This no-op behavior allows test authors to intersperse
     * {@code SerializableTester} calls with other, GWT-compatible tests.
     *
     * <p>Note that the specified object may not be known by the compiler to be a {@link
     * java.io.Serializable} instance, and is thus declared an {@code Object}. For example, it might
     * be declared as a {@code List}.
     *
     * <p>Note also that serialization is not in general required to return an object that is
     * {@linkplain Object#equals equal} to the original, nor is it required to return even an object
     * of the same class. For example, if sublists of {@code MyList} instances were serializable,
     * those sublists might implement a private {@code MySubList} type but serialize as a plain {@code
     * MyList} to save space. So long as {@code MyList} has all the public supertypes of {@code
     * MySubList}, this is safe. For these cases, for which {@code reserializeAndAssert} is too
     * strict, use {@link #reserialize}.
     *
     * @return the re-serialized object
     * @throws RuntimeException     if the specified object was not successfully serialized or
     *                              deserialized
     * @throws AssertionFailedError if the re-serialized object is not equal to the original object,
     *                              or if the hashcodes are different.
     */
    public static <T> T reserializeAndAssert(T object)
    {
        T copy = reserialize(object);
        new EqualsTester().addEqualityGroup(object, copy).testEquals();
        Assert.assertEquals(object.getClass(), copy.getClass());
        return copy;
    }
}
